anyone knows how to add two float numbers with currency sign and place the sum into a dataGridview cell?
this is my code:
private void button8_Click(object sender, EventArgs e)
{
double a =0.70;
double b = 0.50;
dataGridView2.Rows[0].Cells[1].Value = "£" + (a+b);
}
if I declare a and b as float it gives error.
if I declare a and b as Double, the result is £1.2 as shown in photo but NOT £1.20 .
I made column 1 properties to contain a currency value ( result = £1.2)
I made column 1 properties to contain a numeric value and the result is same.
how can I make it £1.20?
is there any way to do it?
thank you
The double type doesn't keep track of how many decimal places were there when the result was computed. As far as it is concerned, 1.2 and 1.20 and 1.200 are all the same value.
You want a specific string representation of that number, with exactly two decimal places. The easiest way to get the desired string representation is using a format string. For example, you can do this:
(a + b).ToString("0:00");
In cases where you want to format multiple expressions, you may find this alternative more convenient:
string.Format("{0:0.00} {1:0.00} {2:0.0}", a, b, a + b)
Keep in mind that float and double are tricky. You probably want to handle money using the decimal type instead.
You can use:
dataGridView2.Rows[0].Cells[1].Value = (a + b).ToString("'£'0.00"));
To do this, you need to set a format for the string. Try using this:
dataGridView2.Rows[0].Cells[1].Value = string.Format("£{0:0.00}", a + b)
You can try this:
dataGridView2.Rows[0].Cells[1].Value = "£" + (a+b).ToString("0.00");
Thank you all for your help. now it is solved. I played around with cell format type and suddenly it changed to £1.20.
Definitely keep in mind the explanations given by Theodoros, especially the suggestion to use the decimal type.
That said, an alternative is to use a System.Globalization.CultureInfo. This has the advantage of correctly handling the symbol, decimal digits, decimal separator, group separator, and group sizes. This way you see results such as £1,234,567.89 instead of £1234567.89.
CultureInfo gb = new CultureInfo("en-GB");
string result = (a + b).ToString("c", gb.NumberFormat);
A further advantage is that parsing out the original value is just as easy:
decimal amount = Decimal.Parse(result, NumberStyles.Currency, gb);
Related
Can't find simple way to convert double to string. I need to convert large numbers without distortion. Such as:
double d = 11111111111111111111;
string s = d.ToString();
Console.WriteLine(s);
//1.11111111111111E+19
How to get string value from double value exactly the same as user enter.
11111111111111111111111 => "11111111111111111111111"
1.111111111111111111111 => "1.111111111111111111111"
Any ideas how it can be done?
double is a floating point type. So it has a limited accuracy. In your example, you could do something like this:
double d = 11111111111111111111;
string s = d.ToString("F0");
Console.WriteLine(s);
But as you'll see,this would output 11111111111111100000 instead of 11111111111111111111,so it has lost accuracy in the process. So the answer here is use the right type for the work. If you need a string, use a string variable to store the value.
Edit
This was the question i was trying to find that explains the problem with floating point math., thanks to #GSerg
First of all: 11111111111111111111111 is to large for a double value and also this value: 1.111111111111111111111 since the double max decimal length is 17.
By default, a Double value contains 15 decimal digits of precision,
although a maximum of 17 digits is maintained internally.
For this reason you should use BigInteger and then ToString for formatting the output.
There is also a library in the nuget Directory called BigRational, never used and seems in Beta stage but probably will help in solving this problem.
In general case, you can't do this: user can well input, say 123, in many a way:
123
123.00
1.23e2
12.3E1
123.0e+00
1230e-1
etc. When you convert the user input into double you loose the initial format:
string userInput = ...
// double is just 123.0 whatever input has been
double value = double.Parse(userInput);
In case you want to drop exponent if it's possible you can
double value = 11111111111111111111;
string result = value.ToString("#######################");
And, please, notice, that double has 64 bit to store the value, that's why a distortion is inevitable for large numbers:
// possible double, which will be rounded up
double big = 123456789123456789123456789.0;
// 1.2345678912345679E+26
Console.WriteLine(big.ToString("R"));
// 123456789123457000000000000
Console.WriteLine(big.ToString("###########################"));
May be you want BigInteger instead of double:
using System.Numerics;
...
BigInteger value = BigInteger.Parse("111111111111111111111111111111111");
// 111111111111111111111111111111111
Console.WriteLine(value.ToString());
Currently have a working rounding model within my c# code and is perfectly rounding numbers that have more than 2 decimal places down to 2 decimal places which is great. However, when i have lets say double value = 100.6, and i put that into double dollar_value = Math.Round(value, 2), it still returns as 100.6.
I was wondering if there was a way to transform a 1 decimal place value to 2 decimal places?
Numbers are not stored with extra zeroes (As it is a waste of memory to do so, being the numbers are the same with or without). In order to represent a number this way you will either need to display or store it as a string.
string str = value.ToString("#.00", CultureInfo.InvariantCulture);
Now str will always have 2 decimal places.
I don't know the C# method, but in C++ I'd use one of these two methods:
double value = 23.666666 ; // example
value = 0.01 * floor ( value * 100.0 ) ; // There's a "floor" function in C# too
^ See https://msdn.microsoft.com/en-us/library/e0b5f0xb(v=vs.110).aspx
Or
double value = 23.666666 ; // example
value = 0.01 * (double) ( (int)(value*100.0) ) ;
Or
double value = 23.666666 ; // example
value = 0.01 * double ( int ( value*100.0 ) ) ; // same as previous, but more C++ like
The other answers are probably better if you're looking to "print a dollar amount with two decimal places." However, if you want to transform the number to use internally, this is a way to do it.
If you want the string representation to have two decimal points use:
yourNumber.ToString ("0.00");
The number itself is always stored as a ~29 digit number regardless of its string representation.
Your value just needs to be formatted when it's display - for example value.ToString("N2") will convert it to a string with two decimal places. Check out the Standard Numeric Format Strings on MSDN to see a broader list of formatting strings.
Additionally, I'd only convert to a string when you're ready display the value to a user and would keep it as a numeric type (e.g. double) if you're passing it around between methods or planning to do any further calculations on it. Otherwise you'll be unnecessarily converting the value to and from a string multiple times.
How to read figure without any symbol??
example -8759.328 and 8569.659"
output should be 8759.32 and 8569.65 in double
var debit = txtDebit.Text.Split('-');
oBankPages.DebitAmount = Convert.ToDouble(debit);
If I understand, you have two strings,
var numberStringOne = "-8759.328";
var numberStringTwo = "8569.659";
If you want to treat these strings like decimals, first you must parse them.
var numberOne = decimal.Parse("-8759.328");
var numberTwo = decimal.Parse("8569.659");
Next, you could get the value ignoring the sign, by using Math.Abs, Abs. being an abbreviation of Absolute.
var numberOne = Math.Abs(numberOne);
Then you convert the number back to a rounded string using the appropriate format specifier.
var formattedNumberOne = numberOne.ToString("D2");
or perhaps
Console.WriteLine("{0:D2}", numberTwo);
so, all on one line.
var formattedNumberOne = Math.Abs(decimal.Parse("-8759.328")).ToString("D2");
Formatting can be done only with strings integral and floating point types doesn't have any formatting by thier own
var res = Math.Abs(-8759.328).ToString("f2");
If at all you need the result as Double you can Round the result
var res = Math.Round(Math.Abs(-8759.328), 2);
Note: above calls Math.Round so result will be rounded rather than formatted. In other words you may get result as 8759.33 instead of 8759.32
oBankPages.DebitAmount = Math.Abs(Convert.ToDouble(txtDebit.Text));
Beware that fractions like these cannot be accurately represented in floating point.You can simply solve it out in your case.
double value = Math.Truncate(100 * Math.Abs(-8759.328)) / 100;
OUTPUT : 8759.32
Try this.
string debit = Regex.Replace(txtDebit.Text, "[^0-9^.]+", "");
oBankPages.DebitAmount = Math.Abs(Convert.ToDouble(debit)).ToString("f");
Use decimal instead of double. Your data is related to money. Even one cent off is significant. You cannot afford to use floats or doubles, as they are lossy data types that remember only the "beginning" of the number and forget the ending. decimal is designed to be precise. If you ever work for financial sector, remember: no floats, no doubles. Of course unless some high-accountant orders tells you they level it up somehow and it's safe due to their creativity..
Read about Salami Attack
On my system, the following code prints '3.6':
double a = 1.2;
int b = 3;
double c = a * b;
Console.WriteLine(c);
But in the debugger, I can see that c has a value with more than 2 digits:
I know that I can display the full representation with Console.WriteLine("{0:R}", c). Is this the only and recommended way to display the actual value of a double?
update
Going with the above example, I'd like to print c such that if the user were to take the printed value and insert that back into the code in a test using ==, the comparison would be true. In this case c == 3.5999999999999996 returns true.
Console.WriteLine calls Double.ToString which uses the the "G" format specifier. This uses the current culture to determine the number of decimal places (1 for "en-US").
If you want to display 8 decimal places you can use the numeric format specifier:
Console.WriteLine(c.ToString("N8"));
Standard Numeric Format Strings
Edit: The debugger uses this method to convert a double to a string:
_ecvt_s
I assume it's the cheapest way to convert it.
Where i have found it: How does Visual Studio display a System.Double during debugging?
3.999999999999996 is not the actual value of the double either; that's just the value rounded off to fifteen places or whatever. There is no built-in way to display the actual exact value that the double is representing. This is really too bad, because every normal double can be represented exactly as a decimal string, and it would be nice to be able to see that.
As a public service, I've put source code for a device which does that on my blog:
http://ericlippert.com/2011/02/17/looking-inside-a-double/
Note that it uses the Rational class from Microsoft Solver Foundation. If you don't have that then you can either download it for free, or write your own Rational class; it's character-building to do so.
If the subject of how doubles work internally interests you, consider checking out my archive of handy articles explaining all that. It's at:
http://blogs.msdn.com/b/ericlippert/archive/tags/floating+point+arithmetic/
Start from the bottom; those are in reverse-chronological order.
You could also use a different approach for example if you want to return 2 decimal places you could try something like this
double a = 1.2;
int b = 3;
double c = a * b;
var s = string.Format("{0:0.00}", c);
Console.WriteLine(s);
Output = 3.60
if you want to suppress the last 0 where out put is 3.6 you could do
var s = string.Format("{0:0.##}", c);
Output = 3.6 feel free to play around with it
double a = 1.2;
int b = 3;
double c = a * b;
string formatted = c.ToString("N5");
Console.WriteLine(formatted);
I want to calculate the percentage. But the compiler is giving an error that the input string is not in a correct format. Can some one elaborate what i am missing here?
private double per()
{
double a = Convert.ToDouble(tbEnglish.Text+tbUrdu.Text+tbPhysics.Text+tbChemistry.Text+tbMaths.Text);
double d = 500;
double lblResult = (a / d)*100;
return lblResult;
}
You're concatenating the strings and then trying to convert that one result into a double. So for results of 75.6, 92.1, 56.3 78.2 and 72.3 you'd end up trying to parse "75.692.156.378.272.3".
Parse each value and then sum them.
However, I would strongly recommend that you use decimal for this instead of double. You should also consider using TryParse instead of Parse so that you can handle user input errors gracefully. Here's the solution sticking with Parse:
public decimal AveragePercentage()
{
decimal sum = decimal.Parse(tbEnglish.Text) +
decimal.Parse(tbUrdu.Text) +
decimal.Parse(tbPhysics.Text) +
decimal.Parse(tbChemistry.Text) +
decimal.Parse(tbMaths.Text);
return sum / 5m;
}
Out of interest, in your original code why are you dividing by 500 and then multiplying by 100? Why not just divide by 5 (as mine does now that I've noticed what was going on)?
As a side note, it's very important to differentiate between compile-time errors and execution-time errors. It wasn't the compiler saying that the input string wasn't in the correct format - it was the Convert.ToDouble method, at execution time. In this case it was relatively obvious, but in other situations we could have been chasing our tails for a while trying to find a compile-time problem when it was actually failing at execution time.
I don't have Visual Studio available to me here on my Linux box, but I think you're better off with code like this.
private double per()
{
double a = Convert.ToDouble(tbEnglish.Text);
a += Convert.ToDouble(tbPhysics.Text);
a += Convert.ToDouble(tbChemistry.Text);
a += Convert.ToDouble(tbMaths.Text);
double d = 500;
double lblResult = (a / d)*100;
return lblResult;
}
In your example, you end up building a string that will look like: "75.692.156.372.3", which cannot be parsed into a double.
You need to convert all the TextBox.Text values into Decimals before using the + operator.